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In a recent shareholder's meeting, someone asked the question about EVs making sounds to alert pedestrians. Elon's response was profound. First, he mentioned that there are two schools of thought on it. Personally, I'm on the "no way" side of it; I think it's noise pollution with insufficient value added. But then Elon demonstrated his brilliance by suggesting a compromise solution that I think everyone, including myself, could get behind. He suggested that cars could make some kind of pleasant sound, but only when it detects people in the way, and he even suggested that the sound be directional. This would be brilliant as it would limit the noise to only when it has potential value, while remaining quiet the other 95+ percent of the time when it's just noise pollution. Personally, I don't think it would need to be directional, but if it can be, all the better.

The cost of such a system could be significant enough that it might not be a good idea for all cars, but it could be made an added cost option. I would pay quite a bit extra for it, myself.

I'm not sure at the moment what the current status of the legislation on this topic is. The last I read, the proposal for the legislation was that EVs make noise under 18 MPH. Hopefully, Tesla is actively paying attention to this and working to ensure any enacted legislation leaves room for companies like Tesla to provide intelligent solutions.

Everyone should continue to pay attention to this topic, as it is important to the future of the EV market. Help to keep awareness high on what's going on, and when possible, help steer this in a good direction. If handled correctly, this win-lose could be made into a win-win for everyone.

Brian H | June 27, 2013

Directional sound is best achieved with two overlapping ultrasonic beams. Where they cross, you hear the difference ('beat frequency'). They can be aimed very precisely, as high frequency sound stays focussed.

GeekEV | June 27, 2013

As for the cost of the other parts of the system, the sensors, when Tesla gets around to adding active safety features like collision avoidance, lane monitoring, adaptive cruise control, etc., they'll have plenty of sensors in place to use. Adding this could be relatively inexpensive...

PorfirioR | June 27, 2013

Here are my thoughts on how such a system could work:

It could be similar to the beep used inside most cars these days for backup alert. Except that this one would be external, directed at the side where a proximity alert was detected, and only active when the car is traveling at slow speed AND a nearby obstacle is detected. Otherwise, no sound at all when backing up or creeping forward.

The closer the pedestrian/byciclist gets, the closer the beeps could get until you reach a flat-line - collision avoidance (brake assist) would then engage IF the potential collision is in the direction of travel.

The system should be able to be turned off for cases where slow transit in the vicinity of pedestrians is needed (i.e. parade mode, sheep herding, driving in New York city...).

How does that sound?

However... what if, like everything else Tesla has done, they just reinvent the whole thing? Why does it have to be a sound? (or only a sound)

You cant always hear ICE cars either, and there is no one claiming we need sounds for those. I think its just another thing that people want to bitch about when it comes to EVs.

People are very "distracted" nowadays, so if they are not paying attention, then they don't notice anyways. Honestly, I don't think a sensor driven "sound" system will do anything substantial. I think it is a superfluous argument, and is a superfluous "solution."

RZippel | June 28, 2013

Without unearthly brilliance, my car makes sounds only if required today. It is called a horn and came without a premium charge.

Honestly, a modern, well isolated ICE you will also almost not hear or hear the tires more than the engine, I think that is a discussion that is entirely not relevant as a EV specific problem.

bent | June 28, 2013

The last I read, the proposal for the legislation was that EVs make noise under 18 MPH

Leading to an effective minimum speed for EVs of 20mph: the unwelcome noise at 18mph will result in a Pavlovian response in the driver causing him, over time, to start never going below 20 except in the case of an imminent emergency. EV drivers will stop their cars by slamming the brakes, to minimize the duration of the noise, and will start them up by slamming the accelerator for the same reason.

What could possibly go wrong?

tes-s.ct.us | June 28, 2013

How about flashing the headlights when sensing people to give a visual cue instead of audio?

carlgo | June 28, 2013

Any technology that detects pedestrians and avoids hitting them would be welcome on any kind of car.

JaneW | June 28, 2013

We used a db meter to check the sound levels of several ICE cars and my Tesla Roadster at
20, 25 and 30 MPH, traffic speeds in towns near crosswalks. We found no difference.
Most ICE cars are very quiet, unless under heavy acceleration. There is no need for extra noise added to electric cars unless they are added to all cars. It is, literally, a moot point, a non-issue.

carlgo | June 28, 2013

Just my finely tuned ear :) but yes, the big noise seems to come from tires on most vehicles. Still, if there is a viable pedestrian avoidance technology I would like to see it used. And I suspect there is.

Brian H | June 28, 2013

tes-s;
Unlikely to be useful to the blind, supposedly one of the "target markets" for noisemaking-warning.

RanjitC | June 29, 2013

@robertzippel
Brilliant!
Maybe we should have a second, lower volume pleasant sounding horn to alert pedestrian's without being perceived as jerks.One that sounds like an ICE engine perhaps?

tes-s.ct.us | June 29, 2013

Audio warning does as much for the deaf as flashing the headlights does for warning the blind.

JaneW | June 29, 2013

"pedestrian avoidance technology"
Some heads up displays have that for night time now.
Different from a technology that warns pedestrians to avoid us.

I have nothing against helping the deaf, blind or even people without those problems be safer pedestrians (big of me, eh?).

My only point is that what is true for EVs is true for ICEVs, too. They all creep up on people.

Seems to me, though, that's why we have traffic lights and crosswalks. Both those can be adapted to have light and sound warnings. Think of a train crossing, only subtle.

carlgo | June 29, 2013

It would be best to have both warnings and avoidance. You can warn people but they may not have the reflexes or nimbleness to actually dodge a car.

There could be radars that spot, identify and categorize obstacles. It would be possible for it to spot a human and automatically apply the brakes, but of course the speed and distance would make this effective or not in any one situation.

Now, what about animals? Would it stop for a dog, a squirrel? What if it stopped for an animal and the person behind you rear-ended you? People could be hurt, tens of thousands of dollars worth of damage could result. Decisions would have to be made, ones that would not please everyone.

And of course who doesn't remember the Simpson's episode where evil Mr. Burns uses the star on the hood of his big Mercedes as a sight to more accurately target peasants to run over.

GuyDormehl | July 1, 2013

I actually think this is a stupid red-herring. As posters say many modern ICE cars are dead quiet at low speeds and not 'noticed' in a noisy street. Surely the average normal person looks before they wander into the road whether they 'hear' a car or not - we can't save everyone from their own stupidity!

Pedestrian detection systems may be a good idea but the mere thought of EVs driving around emitting phoney sci-fi or 'artificial' sounds to alert other road users makes my toes curl! We'd be replacing one type of pollution with another.. A driver-operated hooter is a good idea!

BUT if we do need to have a sound emanating from cars too quiet for comfort (including ICE cars - no discrimination here) at low (but dangerous) speeds up to a point where the general road/wind noise is adequate, let's have 'organic' sounds.

Two suggestions :- the sound of a car on gravel (very relaxing and immediately recognisable) OR the sound of a horse trotting (!) Both should vary in accordance with speed to give a clearer indication to the outside person (the 'horse' could start to canter at 12mph...!!)

Imagine a 'squad' of vehicles trotting and cantering down the road....